Sprung in "A Summary of the Reactions of Aldehydes with Amines", Chemical Review 26 (1940), pages 293 to 338, discloses reactions of formaldehyde with aniline in the presence of an acid. Various formaldehyde/aniline reaction products are formed depending upon operating conditions. The one closest in structure to the compound of this invention is a polymer with repeating units of the following structure: ##STR4##
It is made by reacting aniline with formaldehyde in the presence of an equimolar quantity of strong acid. When the reaction is carried out in a neutral or slightly acid solution, Sprung teaches isolation of an anhydroformaldehyde aniline cyclic trimer.
It has now been found that when aniline is reacted with a glyoxylate, preferably a C.sub.1 to C.sub.6 alkyl glyoxylate and more preferably methyl or ethyl glyoxylate, instead of formaldehyde, in the presence of a catalytic quantity of acid and in a solvent that is capable of azeotropically removing water, poly-p-phenylamino carboxylate having the following structure is formed: ##STR5## where n is greater than 1 and R is the same as the R of the glyoxylate. This is particularly surprising since one skilled in the art would expect the amine to attack the ester since it is well known in the art that an ester readily reacts with a base evolving an alcohol.
It is also surprising in view of the teaching of Muhlbacher et al. in Z. Naturforsch, 37b (1982), pages 1352 to 1354. Muhlbacher et al. teach the reaction of aniline and ethyl glyoxylate in a benzene solvent to produce the monomer: ##STR6##
Muhlbacher et al. does not teach using an acid in the reaction.
While the new compound is defined by the repeating units and not the end groups, the end groups will be those expected by one skilled in the art. Expected end groups include: ##STR7##
This new composition contains a large number of functionalities which will suggest a variety of potential uses to one skilled in the art. For example, the poly-p-phenylamino carboxylate should be useful in the manufacture of surfactants, thermosetting plastics and flame retardants. Surfactants most likely can be made by transesterification with fatty alcohols. Thermoplastics most likely can be made by cross-linking the carboxylate and amino functionalities of the new polymer. Flame retardants most likely would result from bromination of the phenyl group.